SubToolbox

Merge SRT Files — Sequential or Bilingual

Merge two SRT/VTT files — join sequential parts, or combine two languages into one bilingual track. In-browser.

Quick answer: Drop two subtitle files. Sequential mode joins them as-is (for multi-part files whose timings already account for part two). Bilingual mode aligns the second file's lines under the first's wherever their times overlap — the standard two-line dual-language track.

Drop the first subtitle file

Drop the second subtitle file

Sequential merge joins the cues as-is. If part two restarts at zero instead of continuing, shift it first with the subtitle shifter.

Core facts
SequentialConcatenated as-is; use the shifter first if part two needs an offset
BilingualSecondary cue chosen by maximum time overlap with each primary cue
FormatsEach side independently SRT/VTT/ASS/SBV — mix freely
OutputSRT (or any target format via the converter)
PrivacyRuns in the browser; no upload

What this tool does

Two reasons to merge subtitles, two modes. Sequential merge answers “my episode came in two .srt files”: the cues are concatenated in order, since properly authored parts already carry continuous timings — and if they do not, the page links the shifter to push part two forward first. Bilingual merge answers “I want original language and translation on screen together”: every cue of the primary track is matched to the secondary track's cue that overlaps it most in time, and its lines are appended underneath. Unmatched primary cues simply keep one language, and the page reports how many — so a mismatched pair is visible before you download.

Common uses

  • A two-part episode or split recording needs one subtitle file
  • Language-learning videos with native + translation lines
  • Accessibility mixes: dialogue + [description] track combined
  • Festival or fan releases that ship separate language files

Frequently Asked Questions

When I merge sequentially, part two shows at the wrong time.
The parts' timings overlap or restart at zero. Shift part two by the duration of part one (or the video offset) with the subtitle shifter first, then merge.
How is the secondary language matched in bilingual mode?
For each primary cue, the secondary cue with the greatest time overlap wins and its lines are appended beneath. Cues are not re-timed, so the pair stays aligned with both sources.
Some lines only exist in one language — what happens?
They are kept as-is. The report shows the count of primary cues with no overlapping secondary cue, so you can judge whether the two files actually cover the same span.
Can the two input files be different formats?
Yes — each side is auto-detected, so SRT plus VTT merges as readily as two SRTs.

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